The wake structure at the rear of road vehicle is known to be of prime importance in aerodynamics performances [3]: about 30% of the total pressure drag derives from the rear end of the vehicle. While production vehicle present significant curvature at the rear end, most of fundamental aerodynamic analyses were carried out around simplified car models presenting sharp edges at the rear.udSince recently, very few papers addressed the question of rear edges curvature in aerodynamics performances. Thacker et al. Showed that rounding the edge between the end of the roof and the rear slant suppressed the separation over the rear window and resulted in 10% drag reduction. Fuller et al.Studied the effect on spatial stability and intensity of the pillar vortex when rounding the side rear pillars. For both of these works, the analysis was focused on the flow behaviour over the rear window: the impact of the rear end rounding on the near wake topology was not discussed.udThe current study aims to understand how the use of rounded pillars with respect to sharp edges modifies the flow field (over the body surface and in the near wake) and hence the global drag. Moreover, an “academic” and an “industrial” model will be characterized to discuss the applicability of simplified models to simulate properly the sensitivity of pillars rounding.
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